The subject invention relates to a plastic fastening element intended for installation in a substantially rectangular opening of a support frame or panel. The fastening element includes a head part with a holding portion of substantially rectangular cross section connected thereon. The holding portion includes lamella-form fingers or tabs on its longer sides lying opposite each other. In each case, the fingers are limited in the rim zone by a stay which extends along the holding part.
Already known as state of the art is a fastening element which is designed as a so-called self-centering pine-tree clip (see German Disclosure 3,014,745). As shown therein, there are stays which join directly against the head part and between the stays are lamella-form fingers which project obliquely upward. The problem to be solved was that the lamella-form fingers were to be stressed only within allowable limits while completely performing, however, their holding function.
In this prior fastening element the stays form a stiff, rigid unit, so that this element has only a very slight elasticity. It is thus not in a position, in practice, to compensate the tolerance variations occurring in setting into a rectangular opening of a support.
Also known in the prior art is a so-called plastic stopper which has flexible lamella standing out radially from a solid shaft core. The lamella are distributed over the circumference and are held together in axis-parallel groups (see German Disclosure 3,040,360). Here also, relatively exact dimensions must be held as to the rectangular opening in the support in order to set in this plastic stopper in a functionally secure manner.
Such fastening elements are sometimes used to hold functionally secure strip-form objects, such as decorative strips on motor vehicles. In such case, the correspondingly shaped head parts have lengthwise running zone into which the strips can be pushed sidewise (see German Published Application 2,739,889, German Utility Model 8,004,206, and German Disclosure 2,821,095).
The present invention attacks the problem of designing a fastening element of the kind mentioned, so that it can, even with major tolerance variations occurring in the dimensions of a substantially rectangular opening of a support, exert a secure holding function. While this fastening element is to serve mainly for the holding of the strip-form objects it can be used in other environments and for other purposes.